A symphonic poem or tone poem is a piece of orchestral or concert band music, usually in a single continuous section (a movement) that illustrates or evokes the content of a poem, short story, novel, painting, landscape, or other (non-musical) source. Hungarian composer Franz Liszt first applied the term to his 13 works in this vein. In its aesthetic objectives, the symphonic poem is in some ways related to opera. Whilst it does not use a sung text, it seeks, like opera, a union of music and drama.While many symphonic poems may compare in size and scale to symphonic movements (or even reach the length of an entire symphony), they are unlike traditional classical symphonic movements, in that their music is intended to inspire listeners to imagine or consider scenes, images, specific ideas or moods, and not to focus on following traditional patterns of musical form (e.g. sonata form). This intention to inspire listeners was a direct consequence of Romanticism, which encouraged literary, pictorial and dramatic associations in music. Musical works that attempt to inspire listeners in this way are often referred to as program music, while music that has no such associations may be called absolute music.Some piano and chamber works, such as Arnold Schoenberg's string sextet Verklärte Nacht, have similarities with symphonic poems in their overall intent and effect. However, the term symphonic poem is generally accepted to refer to orchestral works. A symphonic poem may stand on its own, or it can be part of a series combined into a symphonic suite. For example, The Swan of Tuonela (1895) is a tone poem from Jean Sibelius's Lemminkäinen Suite. A symphonic poem can also be part of a group of interrelated works, such as Vltava (The Moldau) as part of the six-work cycle Má vlast by Bedřich Smetana. Also, while the terms ""symphonic poem"" and ""tone poem"" have often been used interchangeably, some composers such as Richard Strauss and Jean Sibelius have preferred the latter term for pieces that were less symphonic in design and in which there is no special emphasis on thematic or tonal contrast.According to Macdonald, the symphonic poem met three 19th century aesthetic goals: it related music to outside sources; it often combined or compressed multiple movements into a single principal section; and it elevated instrumental program music to an aesthetic level that could be regarded as equivalent to, or higher than opera. The symphonic poem remained popular from the 1840s until the 1920s, when the genre suffered a severe decline in popularity.